Additive manufacturing systems can manufacture three-dimensional (3-D) objects by utilizing a mechanism of successively depositing a material to build up a three-dimensional (3-D) object. The additive manufacturing mechanism can include depositing printing agents onto a build material to effect the build up of the 3-D object. 3-D printers can utilize such a mechanism to additively manufacture 3-D objects. 3-D printed objects can be additively manufactured based on a three-dimensional object model.